Device for feeding an abrasive mixture to a lapping machine



Nov. 19, 1963 s. A. BOETTCHER 3,110,991

DEVICE FOR FEEDING AN ABRASIVE MIXTURE TO A LAPPING MACHINE 2 Sheets-Sheet 1 Filed April 16, 1962 INVENTOR.

Nov. 19, 1963 s. A. BOETTCHER 3,110,991

DEVICE FOR FEEDING AN ABRASIVE MIXTURE TO A LAPPING MACHINE Filed April 16, 1962 2 Sheets-Sheet 2 1 H1 2. gj 27 7 7 3 24 1 30 a ,9

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United States Patent 3,110,991 DEVIQIE EUR FEEDlNG AN ABRAEIVE MIXTURE Ti.) A LAPPlNG MACHIINE Stephen A. Boettcher, Evanston, lil., assignor to Speedlap Qorporation, Slrokie, ill., a corporation of Illinois Filed Apr. f6, 1962, Ser. No. 187,698 11 Claims. ((11. 51-463) My invention relates to lapping machines for lapping fiat surfaces, and more particularly to a bench-type lapping machine characterized by compactness and simplicity.

To these ends, I provide a box-like housing serving as a framework supporting mechanisms in a novel manner and I also provide very simple means for feeding the abrasive mixture to the lapping wheel or disk.

My invention is illustrated in the accompanying drawings, in which- FIGURE 1 is a perspective view of the machine;

FIGURE 2 is a plan view thereof;

FIGURE 3 is a vertical sectional view, on a larger scale, of the machine, taken substantially along the line 3-3 of FIGURE 2, looking in the direction indicated by the dot-and-dash line and arrows;

FEGURE 4 is an elevational view, on a still larger scale, of the abrasive containing and feeding device of FlGURE 3, the container being shown in section to reveal the interior parts; and

FIGURE 5 is a view looking into the upper end of the device of FiGURE 4.

Referring now to FIGURE 1, it will be seen that I employ a generally rectangular box-like housing 6, which is preferably for-med of sheet metal, upon and within which to mount the mechanisms of my lapping machine. The housing 6 is formed with fnont and rear walls, side walls, and a top wall 7.

The top wml 7 is provided with a larger circular opening it to receive a lapping wheel or disk 9 which is rotatably mounted to the housing 6- in the following manner: Depending from the top wall '7 and attached thereto at the periphery of the opening 8 by welding or otherwise, as shown in FEGURE 3, is a combined drip pan and supporting member 1d having a generally horizontal wall with a central opening 11 therein, defined by an upturned annular flange port-ion l2. Bolted to the underside of the pan-shaped supporting member Ill) and axially aligned with the opening ll therein is a tubular support 13, carrying a conventional worm drive gear box 1 and an operatively connected, horizontally arranged, drive motor 15. The drive shaft 16 of the gear box 1d carries a driving hub 17 which is keyed thereto at 13. The hub 17 is journaled in the tubular support 13 and projects through the opening 11 in the supporting member ill. The upper end of the hub 17 is formed with an integral annular radial flange portion 19 that presents a shoulder 29 which serves to receive and seat an integral annular flange portion 21 extending inwardly of a central opening 2-2. formed in the lapping disk 9. The flange portions 19 and 21 are clamped together by means of a horizontal retaining disk 23 secured in position by a vertical stem 24 that is threaded into the upper end of the hub 17 and presents a shoulder 25 which bears against the disk 23. The aforedescribcd drive means, which is carried by the supporting member ill, serves to support the lapping disk 9 and to drive the same in a counterclockwise direction as indicated in FIGURE 2.

For purposes to be more fully described hereinafter, it will be noted from FIGURE 3 that the diameter of the opening 22 in the disk 9 is greater than the diameter of the opening 1.1 in the supporting member 1 and that the plane of the lower surface of the disk 9 lies below 3 ,110,991 Patented Nov. l9, 1963 the plane of the upper housing wall 7. Further, the lapping disk 9 is detachably mounted to the hub 17 in the manner indicated to penmit the disk 9 to be reversed, whereby either of two lapping surfaces, which may be of the same or different surface finish, may be presented to work pieces.

Resting on the lapping disk 9 are the retaining and truing rings 25, 26, the upper portions of which are formed with external gear teeth 26a. These rings serve to receive work pieces, as indicated at 27, 27, lying on the lapping surface of the wheel or disk 9, and the circular weight or pressure plates 2%, 28, having hand knobs 28', are laid upon the work pieces.

The rings 2d, 26 are maintained in circumferentially spaced relation by means of a central horizontal roller spacer 29 carried by the drive stem 24 and roller stops 30 mounted on the housing 6 slightly offset forwardly from the radial line of the disk and ring centers as shown in FIGURE 2. When the disk 9 is rotating, the rings 25 are free to rotate on their own axes due to frictional contact with the disk 9, but are prevented from rotating about the axis of the lap wheel 9 by the roller stops fill engaging the rings below the toothed portions thereof. To control the wear effect of the rings 25 on the lapping disk, 1 provide a pinion 3i detachably keyed on the upper end of the drive stem 24 for meshing engagement with the gear teeth 26a of the retaining rings 26. When lapping is being performed, the pinion Ell is removed from the drive stem 24. When corrective treatment of the surface of the lap 9 is required, the pinion 31 is placed on the end of the drive stem 24 whereupon the rings 26 are driven in reverse direction. When the corrective treatment is completed, the pinion 31 is removed from the stem 24. By driving the rings 26 in reverse for selected periods of time, the wear effect of the rings 26 on the surface of the lap Q can be suitably controlled, as set forth in my copending application Serial No. 60,815, filed October 6, 1960.

it is conventional to feed a liquid carrier, such as light oil, with abrasive particles in suspension to the lap wheel or disk during operation, and I provide novel means therefor, which is small, compact, and eifective. The fundamental operation of my abrasive mixture feeding device is based on the principle of the ancient Archimedes screw, and my invention lies in the provision of features adapting it to a lapping machine.

in the top wall 7 of the housing 6, at one side of the lap Wheel 9, a circular opening 32 is provided. Secured to the underside of the wall '7 adjacent to the opening 32, is a mounting bracket 33 that is inclined downwardly at an angle of approximately forty-five degrees, as illustrated in FIGURE 37 Suitably mounted to the underside of the inclined portion of the bracket 33 is a small electric motor 34 having drive shaft 35 leading into reducing gear box 34. The axis of the drive shaft is at a right angle to the mounting bracket 33.

Arranged above the gear box 34, on the inclined axis of the drive shaft 35, is cylindrical container as which has an open upper end and a closed lower end with an axial hub 37 brazed or otherwise suitably secured thereto. By way of axial hub 37, the container 36 is fixedly mounted on the output shaft 37' of gear box 34 for rotation therewith. The output shaft 37' of the gear box is slow-turning, for instance 18 rpm.

As shown in FIGURE 4, an open-ended helically wound tube 33 is fixedly mounted in container 36, with the helical coils thereof concentric with the axis of the container. Circumferentially spaced bafi'le plates 39, preferably of spring metal, are secured along their one edges to the helically wound tube 38. In assembly, the free ends of the baflle plates 39 are pressed radially inwardly to permit disposal of the tube 33 in the container, and-are then released to spring radially outwardly forcibly engaging the walls of the container, whereby the helical tube 33 is fixedly mounted in the container 36, with its lower end near the bottom of the container 36 and its upper end extending out of the container and over the lapping disk 9.

The coils of tube 38 are formed with a helix angle that is greater than the angle between the axis of the helix and horizontal, as is evident from FIGURE 4. When the assembly is at rest, the fluid mixture will stand at the same level in the helical tube and surrounding it. When the assembly is rotated in a clockwise direction as viewed in FIGURE 5, pools of mixture will form on the low side, as indicated in FIGURE 4, and will progress upwardly in the tube; thus a continuous series of pools of mixture moving from the bottom to the top of the tube, from which they pour onto the lapping disk 9. Also, with the rotation of the container 36, the baflie plates 39 aid in agitating the mixture to maintain the abrasive particles in even suspension in the carrier.

Used abrasive mixture flowing from the lapping surface of the disk 9 is collected in the drip-pan supporting member 19. As used abrasive material flows down the outer periphery of the disk 9, a portion is thrown radially outwardly from the lower circumferential edge of the disk and, since the under surface of the disk 9 lies below the plane of housing wall 7, such abrasive material strikes the annular wall of the member 10. The remainder follows the lower surface of lap 9 inwardly, dripping therefrom as it moves along, the residual abrasive material dripping from the lower circumferential edge of opening 22 in disk 9. As the abrasive material drips from the lower surface of the lap 9, it is received by the horizontal wall of the member 19. By arranging the opening 22 with a diameter greater than the diameter of the opening it in the drip-pan member 10, used abrasive material is prevented from reaching the hub 17 and the operating mechanism below.

A drain spout 41 is secured in the base of the drippan supporting member for draining it. A wiper bar 42 is threaded into the driving hub 17 for rotation therewith, and the free end thereof serves to sweep collected abrasive material toward the drain spout 41. The drain spout 41 is inclined downwardly extending through an opening in the side wall of the housing 6.

While I have shown a preferred embodiment of my present invention, it will be understood that various modifications and rearrangements may be made therein without departing from the spirit and scope of my invention.

I claim: 7

1. In a lapping machine, a housing having upper and side walls serving as framework, a supporting member secured to the underside of the upper wall of said housing, said supporting member having a central opening therein, drive means secured to the underside of said supporting member and having a drive shaft extending upwardly through the central opening therein, a horizontal lapping disk secured to and rotatable with said drive shaft above said supporting member, and means for feeding an abrasive mixture to said disk, said supporting member serving to collect used abrasive mixture flowing from said disk.

2. In a lapping machine, a housing having upper and side walls serving as framework, a supporting member secured to the underside of the upper wall of said housing, said supporting member having a central opening therein, drive means secured to the underside of said supporting member and having a drive shaft extending upwardly through the central opening therein, a horizontal lapping disk secured to and rotatable with said drive shaft above said supporting member, means for feeding an abrasive mixture to said disk, said supporting member serving to collect used abrasive mixture flowing from said disk, a drain spout secured in the underside of'said supporting member, and wiper means secured to and rotatable with said drive shaft for causing abrasive material collected in said supporting member to flow toward said drain spout.

3. In a lapping machine, a housing having a top wall and side supports serving as framework, a pan-like member secured at its periphery to the underside of said top wall, said pan-like member having a horizontal bottom with a central opening therein defined by an upturned annular flange, a driving motor mounted to the underside of said pan-like member and having a drive shaft extending upwardly through said central opening, a horizontal lapping disk having a central opening therein with a diameter greater than the diameter of said central opening in said pan-shaped member, said disk having an integral annular radial flange portion extending inwardly of said central opening in said disk, said disk flange being secured to said drive shaft for rotation therewith immediately above said pan-shaped member with the plane of the lower surface of said disk lying below the plane of said upper housing wall, and means for feeding an abrasive material to said disk, said pan-shaped member serving to collect used abrasive material released from the edges of said disk.

4. In a lapping machine, a framework, a lapping disk rotatably mounted on said framework, and means for feeding an abrasive mixture to said disk, said means comprising a container rotatably mounted on an inclined axis alongside said disk, a helically formed tube fixedly mounted in said container, the lower end of said tube being open to the lower interior of said container to receive abrasive mixture therefrom, and the upper end of said tube extending over said lapping disk to feed abrasive mixture therefrom to said lapping disk.

5. In a lapping machine, a framework, a lapping disk rotatably mounted on said framework, means for rotating said disk, and means for feeding an abrasive mixture to said disk, said means comprising a container rotatably mounted on said framework on an inclined axis alongside said disk and being adapted to receive an abrasive mixture, means for rotating said container, a helically formed tube fixedly mounted in said container on an axis coinciding with the axis of said container, the lower end of said tube being open to the lower interior of said container to receive abrasive trnixture therefrom, and the upper end of said tube extending out of said container and over said lapping disk to feed abrasive mixture therefrom to said lapping disk.

6. In a lapping machine, a framework, a lapping disk rotatably mounted on said framework, means for rotating said disk, and means for feeding an abrasive mixture to said disk, said means comprising a container rotatably mounted on said framework on an inclined axis alongside said disk and being adapted to receive an abrasive mixture, means for rotating said container, a helically wound tube disposed in said container with the helical coils thereof being concentric with the axis of said container, circumferentially spaced baffle plates secured along their one edges to said tube and along their other edges forcibly engaging the walls of said container whereby said tube is fixedly mounted in said container, the lower end of said tube being open to the lower portion of said container to receive abrasive mixture therefrom, and the upper end of said tube extending out of said container and over said lapping disk to feed abrasive mixture therefrom to said lapping disk.

7. For use with a lapping machine having a framework and a lapping disk rotatably mounted on the framework, the combination of a container rotatably mounted on the framework on an inciined axis alongside the disk and being adapted to receive an abrasive mixture, means for rotating said container, a helically wound tube fixedly unounted in said container with the helical coils thereof being concentric with the axis of said container, the lower end of said tube being open to the lower portion of said container to receive abrasive mixture therefrom, and the upper end of said tube extendnig over the lapping disk to feed abrasive mixture therefrom to the lapping disk.

8. For use with a lapping machine having a framework and a lapping disk rotatably mounted on the framework,

the combination of a container rotatably mounted on the framework on an inclined axis alongside the disk and being adapted to receive an abrasive mixture, means for rotating said container, 2. helically wound tube disposed in said container with the helical coils thereof being concentric with the axis of said container, circumferentially spaced bafile plates secured along their one edges to said tube and along their other edges forcibly engaging the Walls of said container whereby said tube is fixedly mounted in said container, the lower end of said tube being open to the lower portion of said container to receive abrasive mixture therefrom, and the upper end of said tube extending over the lapping disk to feed abrasive mixture therefrom to the lapping disk.

9. A device for feeding a freely flowing material to a machine tool comprising a container rotatably mounted on an inclined axis and being adapted to receive a freely flowing material, means for rotating said container, a helically wound tube fixedly mounted in said container, the lower end of said tube being open to the lower portion of said container to receive material therefrom, and the upper end of said tube opening outwardly of said container to feed material therefrom upon rotation of said container.

10. A device for feeding a freely flowing material to a machine tool comprising a container rotatably mounted on an inclined axis and being adapted to receive a freely flowing material, means for rotating said container, a helically wound tube disposed in said container with the helical coils thereof being concentric with the axis of said container, circumferentially spaced baffle plates secured along their one edges to said tube and along their other edges forcibly engaging the walls of said container whereby said tube is fixedly mounted in said container, the lower end of said tube being open to the lower portion 6 of said container to receive material therefrom, and the upper end of said tube opening outwardly of said container to feed material therefrom upon rotation of said container.

11. A device for feeding a freely flowing material to a machine tool comprising a container rotatably mounted on an inclined axis and being adapted to receive :a freely flowing material, means for rotating said container, at helically wound tube disposed in said container with the helical coils thereof being concentric with the axis of said container, said helical coils having a helix angle greater than the angle of the axis of said container, circumferentially spaced bafile plates secured along their one edges to said tube and along their other edges forcibly engaging the walls of said container whereby said tube is fixedly mounted in said container, the lower end of said tube being open to the lower portion of said container to receive material therefrom, and the upper end of said tube opening outwardly of said container to feed material therefrom upon rotation of said container.

References Cited in the file of this patent UNITED STATES PATENTS 389,071 Glessner Sept. 4, 1888 1,074,043 Breur Sept. 23, 1913 1,114,160 Macbeth Oct. 20, 1914 1,134,944 Boyle Apr. 6, 1915 1,666,713 Maynard Apr. 17, 1928 1,720,999 Cawley July 16, 1929 2,722,785 Porter et a1. Nov. 8, 1955 OTHER REFERENCES Reeber, German application Serial No. R 15099, print ed Feb. 23, 1956 (lb/67a), 2 pp. spec., 1 sheet dwg. 

9. A DEVICE FOR FEEDING A FREELY FLOWING MATERIAL TO A MACHINE TOOL COMPRISING A CONTAINER ROTATABLY MOUNTED ON AN INCLINED AXIS AND BEING ADAPTED TO RECEIVE A FREELY FLOWING MATERIAL, MEANS FOR ROTATING SAID CONTAINER, A HELICALLY WOUND TUBE FIXEDLY MOUNTED IN SAID CONTAINER, THE LOWER END OF SAID TUBE BEING OPEN TO THE LOWER PORTION OF SAID CONTAINER TO RECEIVE MATERIAL THEREFROM, AND THE UPPER END OF SAID TUBE OPENING OUTWARDLY OF SAID CONTAINER TO FEED MATERIAL THEREFROM UPON ROTATION OF SAID CONTAINER. 